Wireless remote monitors employing reassurance tones

Abstract

A wireless audio monitoring system includes a reassurance tone generator for providing the user with assurance that a receiving unit is within range of the monitoring unit's transmitter and that both are operating properly. The reassurance signal is a brief audible tone transmitted at regular intervals by the monitoring unit to the receiving unit. The reassurance tone is either injected as sound into the monitoring unit's microphone, as an electronic signal into the microphone's amplifier or directly into the transmitter. A typical reassurance tone is a quarter-second long audible tone that occurs every ten seconds. At the receiving unit, the user has the option of either hearing or not hearing the reassurance tone by either eliminating the tone itself or by muting the loudspeaker during the time the reassurance tone is being received. Alternatively, the reassurance tone is turned on or off at the monitoring unit by means of a radio control signal sent from the receiving unit.

What is claimed is: 
     
       1. A wireless monitoring system comprising: a transmitter including an audio pickup device for monitoring ambient sounds and means for transmitting said ambient sounds,   a tone generator for causing said transmitter to transmit an occasional audible reassurance tone,   a receiver tuned to receive the ambient sounds monitored by said transmitter, and said receiver including means for receiving said reassurance tone, and   means associated with said receiver for selectively controlling the monitoring of said reassurance tone while continuing to monitor said ambient sounds.   
     
     
       2. A wireless sound monitoring system comprising: a monitoring unit, said monitoring unit including: a microphone,   a transmitter connected to said microphone for broadcasting on a radio frequency signal ambient sounds picked up near the monitoring unit, and   a tone generator for causing said transmitter to broadcast on said radio frequency signal short duration, fixed frequency reassurance tones; and   a receiving unit, said receiving unit including: a receiver tuned to the radio frequency signal from said transmitter,   means within said receiver for detecting and converting the ambient sounds and reassurance tones contained in said radio frequency signal into an audio output signal, and   means for selectively removing from said audio output signal said reassurance tones.       
     
     
       3. The wireless sound monitoring system of claim 2 wherein said tone generator includes: a tone generating circuit for producing said reassurance tone, and   a timing circuit for causing said reassurance tone to be applied to said transmitter for short periods of time at regular intervals.   
     
     
       4. The wireless sound monitoring system of claim 3 wherein said short period of time is approximately 0.2 seconds in length and wherein said regular intervals are every ten seconds. 
     
     
       5. The wireless monitoring system of claim 2 wherein said means for selectively removing said reassurance tones includes: a notch filter tuned to the frequency of said reassurance tones, and   a switch for enabling said notch filter to remove said reassurance tones from said audio output signal of said means for detecting and converting.   
     
     
       6. The wireless monitoring system of claim 2 wherein said transmitter includes means for generating control signals substantially simultaneously with said reassurance tones; and wherein said means for selectively removing said reassurance tones includes: means for detecting said control signals, and   means for muting said audio output signal during an interval when said control signals are present.     
     
     
       7. The wireless sound monitoring system of claim 6 wherein said receiver includes a loudspeaker and a low pass filter for preventing audio signals above a predetermined frequency from being applied to said loudspeaker; and wherein said control signals are high frequency audio signals above said predetermined frequency.   
     
     
       8. The wireless sound monitoring system of claim 2 wherein said monitoring unit further includes a voice actuated relay circuit responsive to ambient audio sounds above a predetermined amplitude for causing said transmitter to emit radio frequency signals. 
     
     
       9. The wireless monitor system of claim 2 wherein said receiving unit includes a control transmitter for generating a control signal, a muting switch for controlling the operation of said control transmitter,   a control receiver within said monitoring unit tuned to the frequency of said control transmitter,   and circuit means connected to said control receiver and responsive to said control signal generated by said control transmitter for controlling the operation of said tone generator.   
     
     
       10. A monitoring unit for use in a wireless monitoring system including a receiver unit, said monitoring unit comprising: an audio pickup device for receiving ambient sounds near of said monitoring unit,   a signal generator for generating a reassurance signal,   a transmitter for transmitting said ambient sounds and said reassurance signal on a radio frequency signal from said monitoring unit to a receiver unit; and   wherein said reassurance signal comprises a signal for indicating that said monitoring unit is operable to transmit said ambient sounds to said receiver unit.   
     
     
       11. The wireless sound monitoring system of claim 10 wherein said reassurance signal comprises a fixed frequency tone. 
     
     
       12. The monitoring unit of claim 10 wherein said reassurance signal comprises a plurality of signals transmitted at predetermined spaced intervals. 
     
     
       13. A method of monitoring ambient sounds at a predetermined location using a wireless sound monitoring system comprising the steps of: placing a monitoring unit at said predetermined location,   providing a receiver unit in spaced relation to said monitoring unit,   receiving ambient sounds near said monitoring unit and transmitting said ambient sounds from said monitoring unit to said receiver unit on a radio frequency signal,   generating and transmitting a reassurance signal from said monitoring unit,   receiving said reassurance signal at said receiver unit whereby operation of said wireless sound monitoring system is verified; and   wherein said receiver unit provides an indication of said reassurance signal being received at said receiver unit and further including the step of disabling, at said monitoring unit, said transmission of said reassurance signal while continuing to transmit said ambient sounds from said monitoring unit to said receiver unit on said radio frequency signal.   
     
     
       14. A wireless sound monitoring system comprising: a monitoring unit including a reassurance signal generator for generating a reassurance signal and an audio pickup device for receiving ambient sounds near said monitoring unit, and a transmitter for transmitting said reassurance signal and said ambient sounds on a radio frequency signal,   a receiver unit for receiving said radio frequency signal, said receiver unit including means for indicating a condition wherein said reassurance signal is not received by said receiver unit; and   wherein said receiver unit includes means for selectively controlling said means for indicating said condition whereby said means for indicating said condition is disabled while continuing to monitor said ambient sounds.   
     
     
       15. The wireless sound monitoring system of claim 14 wherein said reassurance signal comprises a short duration, fixed frequency signal. 
     
     
       16. A method of monitoring ambient sounds at a predetermined location using a wireless sound monitoring system comprising the steps of: placing a monitoring unit at said predetermined location,   providing a receiver unit in spaced relation to said monitoring unit,   receiving ambient sounds near said monitoring unit and transmitting said ambient sounds from said monitoring unit to said receiver unit on a radio frequency signal,   generating and transmitting a reassurance signal from said monitoring unit,   receiving said reassurance signal at said receiver unit whereby operation of said wireless sound monitoring system is verified; and   wherein said receiver unit provides an indication of said reassurance signal being received at said receiver unit and further including the step of disabling, at said receiver unit, and indication of said reassurance signal being received while continuing to monitor said ambient sounds transmitted from the monitoring unit.   
     
     
       17. The method of claim 16 including the step of filtering said reassurance signal from said ambient sounds at said receiver unit. 
     
     
       18. The method of claim 16 further including the step of: said receiver unit converting said radio frequency signal into an audio output signal corresponding to said ambient sounds.   
     
     
       19. The method of claim 18 wherein said receiver unit continues to convert said radio frequency signal into said audio output signal corresponding to said ambient sounds after said step of disabling said indication of said reassurance signal being received.